<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<style type="text/css">
			.big{
				width: 500px;
				height: 500px;
				background: lightblue;
				position: relative;
				left: 300px;
				top: 200px;
			}
			.box1{
				width: 100px;
				height: 100px;
				background: red;
				position: absolute;
				z-index: 3;
				
			}
			.box2{
				width: 200px;
				height: 200px;
				background: yellow;
				position: absolute;
				z-index: 2;
			}
			.box3{
				width: 300px;
				height: 300px;
				background: lightgreen;
				position: absolute;
				z-index: 1;
			}
		</style>
	</head>
	<body>
		<div class="big">
			<div class="box1"></div>
			<div class="box2"></div>
			<div class="box3"></div>
			<div class="box4"></div>
			<div class="box5"></div>
		</div>
	</body>
</html>
